The HK USP (Universal Self-loading Pistol) is the first service pistol based on a modular concept. During development of the USP, the requirements of the Military and Security forces have consistently been taken into consideration. Thanks to the use of an improved Browning locking system with a patented buffer system, the USP recoil behaviour is unobtrusive even during the use of the highest powered ammunition. The buffer system reduces recoil forces and increases both service life of the pistol as well as improves recoil behaviour. The modular design of the USP enables an individual adaptation of safety and trigger mechanisms to any requirement.

• The operation of the pistol - recoil operated weapon with locked breech and tilting barrel
• Braking of unlocking and buffer blow via a spring element
• Grip and magazine made of glass fibre reinforced polymer with corrosion proof metal inserts
• Calibre exchange between 9 mm x 19 and .40 S & W possible by replacing slides, barrels and magazines
• Modular design with customer-specific design possibilities, for example:
  - SA/DA Variant Double Action/Single Action with safety lever for safety and de-cocking function, arranged on the right or left side
  - SA/DA Variant Double Action/Single Action with safety lever only for de-cocking function, arranged on the right or left side
  - Variant DA Double Action with safety lever for safety function, arranged on the right or left side, without de-cocking lever
• Integrated support rail for aiming units
• Magazine capacity 15 cartridges (9 mm x 19), 13 cartridges (.40 S & W), 12 cartridges (.45 Auto)
• Open square notch rear sight with contrast points
• Hammer strut lock (Gun lock) with key upon request.